I'd like to post another reminder that Bukkit 1.7 will be ready in the coming weeks and share with you the implications this has for the Minecraft server.
First, we're still running v1.6.4 and will be until Bukkit is updated. If haven't updated in a while, you might be running v1.6.2. If so, the protocol version has been bumped since then and you will not be able to connect to the server as it is currently configured. You'll need to follow the instructions here on how to update to a specific version (except that you'll need to select 1.6.4 instead of 1.6.2). Of course, you'll have to go through the same instructions a second (or third?) time in order to update to 1.7, but the expected benefit with maintaining a separate profile is that you won't be following the Minecraft releases as they come out. This allows you to select a specific version and stick with it as long as we're running it. The only downside is that it does require some effort on your part to maintain.
Second, the 1.7 update dramatically changes the world generator and introduces many new biome types and variations to existing biomes. The general consensus is to keep the existing world but change the default to a newly generated one. This way, you'll be able to access all of your previous resources and facilities while taking advantage of the new world. We'll probably suggest shuttling materials from the old world into the new as time allows and as you begin to build new structures. The idea is to keep the old world around for a little while and give you the opportunity to take advantage of the work you've already done. I don't know how long we'll keep the old world, but access will probably be granted through Multiverse indefinitely or until plugins break. (Of course, this assumes Multiverse will work with 1.7 in which case we may have to figure out alternatives.)
So for now, update to v1.6.4 if you haven't already. Then hang tight for the 1.7.x update.